AI 中文总结
针对离散调制CV-QKD，提出多环M-APSK星座优化方法，优化环半径比与概率，使16-APSK最大传输距离延长约15%，小尺寸星座优化增益更显著。
AI 中文摘要
本文针对离散调制连续变量量子密钥分发（CV-QKD）提出了一种多环M-APSK星座优化方法。与具有固定环间距和预定义环概率的传统APSK结构不同，该方法优化环半径比和环概率以提升有限尺寸下的密钥率。采用基于Gram矩阵的方法计算平均态τ的非零谱，并利用保真度对比优化后的离散平均态与高斯平均态。结果表明，与传统二项式APSK结构相比，所提结构使16-APSK的最大传输距离延长约15%；对于小尺寸APSK星座，优化增益更大，因其平均态与高斯调制的结构差距更显著。
英文摘要
This paper proposes a multi ring M-APSK constellation optimization method for discrete-modulated continuous variable quantum key distribution. Unlike conventional APSK structures with fixed ring spacing and predefined ring probabilities, the proposed method optimizes the ring radius ratio and ring probability to improve the finite-size secret key rate. A method based on the Gram matrix is used to calculate the nonzero spectrum of the average state $τ$, and fidelity is used to compare the optimized discrete average state with the Gaussian average state. The results show that the proposed structure extends the maximum transmission distance of 16-APSK by approximately 15% compared with the conventional binomial APSK structure. The optimization gain is larger for small size APSK constellations, where the average state has a larger structural gap from Gaussian modulation.
Comments16 pages, 6 figures, 2 tables, An earlier conference version covering the 16-APSK results has been accepted for presentation at APWCS 2026
